Designed for high rpm, BC valve springs are would from only the highest grade, super clean, chrome silicone alloy and feature proprietary processing procedures for consistent pressures. BC titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances. Spring Pressure: BC1220 Seat: 1.550" @ 95lbs/ Open: 0.990" @ 236lbs / Coil Blind: 0.900" (no machine work required)